feat: use process_metadata_outputs for output mapping in command plugin

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/meta_plugin/command.rs

@@ -156,11 +156,14 @@ impl MetaPlugin for MetaPluginCommand {
                     debug!("META: Program output: {}", result);
                     self.result = Some(result.clone());
 
-                    // Create metadata to be returned
-                    metadata.push(crate::meta_plugin::MetaData {
-                        name: self.meta_name.clone(),
-                        value: result,
-                    });
+                    // Use process_metadata_outputs to handle output mapping
+                    if let Some(meta_data) = crate::meta_plugin::process_metadata_outputs(
+                        &self.meta_name, 
+                        serde_yaml::Value::String(result), 
+                        &self.outputs
+                    ) {
+                        metadata.push(meta_data);
+                    }
                 }
             } else {
                 debug!("META: Program failed with status: {:?}", output.status);